Cb characteristics of a transistor 3

Current follower[ edit ] Figure 3: If the output voltage VCB applied to the collector-base junction JC is further increased, the depletion region width further increases. From the above figure, it is seen that the width of the base region is very thin.

Electronic Devices and Circuits Questions and Answers – The CB Characteristics

When the emitter current or input current IE is equal to 0 mA, the transistor operates in the cut-off region. Voltage amplifier[ edit ] Figure 2: The cut in voltage of a silicon transistor is 0.

In common base configuration, the base terminal is grounded so the common base configuration is also known as grounded base configuration. In other words, the common base amplifier attenuates the electric current rather than amplifying it. The output current or collector current IC is taken along the y-axis vertical line and the output voltage VCB is taken along the x-axis horizontal line.

To fully describe the behavior of a transistor with CB configuration, we need two set of characteristics: This phenomenon is known as punch through.

This region is known as the active region of a transistor.

Transistor Characteristics

From the above characteristics, we can see that for a constant input current IE, when the output voltage VCB is increased, the output current IC remains constant.

Thus electric current is produced at the base and emitter region. Current flow in common base amplifier For the sake of understanding, let us consider NPN transistor in common base configuration.

The inclusion of rO in the hybrid-pi model predicts reverse transmission from the amplifiers output to its input, that is the amplifier is bilateral. Common base circuit with Norton driver; RC is omitted because an active load is assumed with infinite small-signal output resistance Figure 3 shows the common base amplifier used as a current follower.

This type of transistor arrangement is not very common and is not as widely used as the other two transistor configurations. The input resistance of common base amplifier is very low.

The current gain or current transfer ratio is defined as the ratio between the emitter input current and the collector output current: At saturation region, both emitter-base junction JE and collector-base junction JC are forward biased.

The supply voltage between base and emitter is denoted by VBE while the supply voltage between collector and base is denoted by VCB. After we kept the input current IE constant at 1 mA, the output voltage VCB is increased from zero volts to different voltage levels. For example, in an application like this one where voltage is the output, a g-equivalent two-port could be selected for simplicity, as it uses a voltage amplifier in the output port.

Therefore, the emitter current is greater than the base current and collector current. On the other hand, the collector-base junction JC at output side acts somewhat like a reverse biased diode.Output Characteristics for CB Configuration of Transistor The output characteristics of CB configuration (Figure 3) show the variation of collector current, I C with V CB when the emitter current, I E is held constant/5(11).

Transistor and their Characteristics – Lesson-1 Junction Transistor. Junction Transistor Unit 4 Lesson 1- ", Raj Kamal, 2 Characteristics of Transistor Amplifier in three characteristics right of V CB = 0 and I C first.

A Bipolar Junction Transistor (BJT) has three terminals connected to three doped semiconductor regions. In an NPN transistor, The collector characteristics of the common-base (CB) and common-emitter (CE) configurations have.

Common base

The input characteristics of a CB transistor resembles_____ a) Forward biased diode b) Illuminated photo diode c) LED d) Zener diode View Answer. Answer: b Explanation: The input characteristics resemble the illuminated photo diode and the output characteristics resemble the forward biased diode.

This transistor has low input impedance and high. Transistor CB (Common Base) configuration It is transistor circuit in which base is kept common to the input and output circuits.

Characteristics: • It has low input impedance (on the order of 50 to Ohms). Bipolar Junction Transistor. Common Base Configuration. In common base configuration, emitter is the input terminal, collector is the output terminal and base terminal is connected as a common terminal for both input and output.

To determine the input characteristics, the output voltage V CB (collector-base voltage) is kept.

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Cb characteristics of a transistor 3
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